“Not all areas that could be forested should necessarily be forested,” Chazdon says. Taking the local ecosystems into consideration, as well as the impact of trees on the communities nearby, is essential in making global tree restoration viable. In other words, battling climate change with carbon-sucking trees requires more planning and strategy than just planting trees everywhere we can. [...]

The implications of putting trees where they don’t belong could be serious. Misplaced flora could kill local ecosystems, weaken biodiversity, dry up water supplies and make areas more prone to fires. Countries like Japan and Ireland are already experiencing the consequences of poorly planned tree planting initiatives. The use of just one or two tree species to replant in those countries has led to ecological disruptions.

Any ecoengineering is going to require a lot of planning and thought. There are countries thought that formerly had huge forests that we should really think about replanting. Spain is an example as it's forest went to supply its navy leaving the country less green than it had been. I also think if we could reforest the Amazon that would be a big step in the right direction.